Azo dye and process of making same.



nnrrnn s'r 'rns PATENT o FioE,

WILHELM HERZBERG, OF BERLIN, GERMANY, ASSIGNOR TO ACTIEN GESELLSCHAFT FUR ANILIN FABRIKATION, OF BERLIN, GERMANY.

A DYE ANDPROCESS To all whom it may concern:

Be it known that I, WILHELM HERZBERG, of Berlin, in the Kingdom of Prussia, German Empire, have invented new and useful lmproyen'ien-ts in new Azo Dvestufl' and Process of Makim Same; and i do hereby declare that the fo llowin is a full, clear, and exact description thereoT, which will enable others skilled in the art to which it appertains to make and use the same.

My present invention relates to the. manufacture of a new azo dyestuii. as l have found .that by diazotizing and then co1nbin ing di-ortho-dianisidindisulfouic acid with beta-naphthol there is obtained a red azo dye of great technical value, this dyestufl when dyed on wool in an acid-bath being distinguished by a clear bluish-red tint, and the dye thus obtained being fast to washing and acid or alkaline milling.

As to the production of the diorthodianis idindisulfonio acid, which is to be diazotized and then combinedwith beta-naphthol, according to my present invention, it is convenient to say that this acid maybepreparedby the action ,of fuming sulfuric acid on diortho-dianisidin at temperatures between 0 and about 30 centigradc- The neutral sodium salt of this new sulfonic acid. is obtained in the shape of small leaves of a silvery luster, containing water of crystallization by cooling a hot concentrated aqueous solution new sull'onic acid most of this salt, as it dissolves in about ten times its Weight of hot water ,but diflicultly soluble in cold water, whereas the free disulfonic acid is very easily soluble .in Water. This probably has the following constitution:

The following example may serve to illustrate my invention the parts being by v weight:

with the addition of thirty-five parts of hydrochloric acid, (20 Baumspccilic gravity.) To thls solution are added seven parts of g sodium nitrite in an aqueous solution while stirring well. The diazotization being finished, the diazo solution is allowed to run Specification of Letters Patent.

Anplieation filed 0mm 26, 1905. Serial No. 340,689.

OF MAKING SAME,"

Patented Jam-29, 1907.

into a beta-haphthrfl solution, which is prepared from 14.5 parts of betamaphtho b dissolving it in about two hundred parts of water with the addition of twelvciarts of caustic soda-lye, (40 Baum, speci ic gravity.) and Of an atpleous solution of twentytwo parts of CLJlDQd sodium carbonate.

Combination occurs in1mediately,the dycj stufi' separating out and 1s complete after a After filtering the residue is mon salt, and then boiled for some time, the dy estull separating out as a crystalline powder. P It is filtered and dried.

crystalline powder soluble in water to abluea The product thus obtained forms ajred red-solution, which solution separates avio- 1 let precipitate by the addition of concenf trated hydrochloric acid and a brick-red precipitateby the addition of concentrated soda-lye. In concentrated sulfuric acid it dissolves with: a blue-red coloration, from which solution on the addition of ice separates i a blue-red preci itate. without a mor ant in an acidath, (acetic acid or the like,) clear bluish-red tints areob tained, which are fast to washing and It is obvious-that the present invention is not limited to the foregoing example nor to the details given therein. Especially when instead of the di-ortho-dianisldindisulfonic acid in the foregoing example another diortho-dialkyloxybenzidindisulfoni acid is used-as, for instance, di-ortho-diphenetidindisulfonic acidthere is also obtained a red azo dyestufl dyeing wool without a mordant from an acid-bath clear red tints, which are fast to washing and milling. Having now described my invention and the manner in which the same is :to be performed, what I clai1nis I 1. The process of producing red azo dyestufl's consisting in diazotizing aadi-orthodialkyloxybenzidindisull'onic acid and combining the diazo compound thus obtained acid and then combinin the diazo com :pound 'thus obtained with betarnaphthol.

producing a red azo dye-- 3. As a new article of maruifacturev ,an azo from an acid-bath clear real tints which are g fast to Washing and milling.

Q. As a new article of nmnufacture the 'herelnbefore described monoazo dyestuli i dyeing woolwithout a inordant in an acidbsth bluish-red tints which are fast to washing and milling, this (lyestufl' being in the shape of the sodium salt a red crystalline powder dissolving in water to a blue-red solntion,-wi1icl1 solution separates a violet pie cipitste by the addition oiconcentrated by (lrochloric acid and a brick-red precipitate'by the aalclition of concentrated soda-lye, which (lyestutl dissolves in concentrated sulfuric acid with a blue-red coloration from which solution on addition of ice separates at bluered precipitate and which (lyest-ufi' when treated with a strong reducing agent yields (ii-ortho-dizinisidindisulionic acid besides 1.2 amidonaphthol.

In witness whereof I have hereunto signed my name, this 8th day of October, 1906, in the presence of two subscribing witnesses.

WILHELM HEBZBERG. Witnesses: I

WoLnnMAR HAUPT, HENRY HAsPEn. 

